The conventional welder's helmet includes a headband that fits around the forehead of the welder. An opaque shell or hood is pivotally mounted to the headband so that it can be pulled down in front of the welder's face, or pushed up out of his line of sight. A sight window is formed in the middle of the shell in front of the welder's eyes while he makes a weld or cut. A welder's filter glass is fitted into the window. This is an especially formulated glass which filters out the dangerous wavelengths from the arc or flame, and also reduces the total transmissivity of light so that only a small amount of the very intense light is passed by the filter glass. One common formulation of glass for this purpose is called "Crook's Glass".
The sight window is generally made only large enough for the welder to see the immediate area where the arc or flame is applied. The remainder of the hood is opaque and impedes the welder's view in his forward line of sight, and also in the area where he would usually enjoy peripheral vision, and which for his safety he should have.
The filter glass is very dark, so that the welder can look directly at the arc or flame, and at the molten metal which they create. These are very intense light sources, so it is not surprising that in order to enable this essential function, their transmission is so reduced that the welder cannot effectively see anything which is under ordinary or under merely very bright illumination, such as shop or floodlight illumination. For this reason, this shell is pivotally mounted. Then the welder can pivot the shell up out of the way and see his work in the ordinary light. This enables him to make his set-ups and to inspect his work, and locate himself and his equipment relative to the set-up.
There are very objectionable consequences to this conventional arrangement. One is that when the welder drops the shell in front of his eyes (usually by sharply nodding his head) he is momentarily disoriented because he does not dare to strike his arc or light the flame until his eyes are protected. As another objection, his side and peripheral vision are cut-off by the shell so that he is unable to react to or to protect himself from events which may be occurring around him. For example, he should be aware of objects moving in a direction to strike him or the presence of another person who should not be present when the welder strikes his arc or lights his flame, and the shell blocks these off.
Still another problem is that, when the welder raises the shell, it may be that a nearby arc or flame of a co-worker will be initiated. Then the glare might strike his eyes from the side, to his vision detriment.
Quite apart from the above and other risky situations, welders will agree that it would be much more convenient for them to be able to see even a limited field of view under ordinary illumination with the shell down, and it would be especially advantageous to have peripheral vision with the shell down when the arc or flame is initiated. This will minimize the risks during lifting and lowering the shell, and make the welder more aware of his surroundings. It will decrease his sense of isolation, and increase his safety. The need frequently to accommodate to different levels of illumination and the need to reorient oneself immediately before and after an arc or flame is initiated can be very bothersome. However, to provide these advantages will require a light path which is open when the flame and arc are initiated.
It is an object of this invention to provide a welder's helmet with both a conventional window fitted with welder's glass, and with auxiliary vision means which will permit the welder to look outside his helmet under all operating conditions, and which therefore is much less dark, if it is dark at all.